Technical Lets Play a Game, Engine diagnostics

Yeah, thought of that after I posted it. Thought about editing the original post, but here we are. Maybe the OG puts up a "P***" allowing someone else to go.

@FrozenMerc, It would be cool to keep it hot rod specific, but I'm sure it could sway in other directions from time to time.

3blap.

 

This one is fuel type agnostic and it happened on my hot rod hauler, so it is close.

Motor: IH 420 ci Diesel V8.

Story: I spent a weekend pulling the heads, swapping head gaskets, and replacing the head bolts with studs. Got the engine back together, primed the fuel system, and she fired back up right away. Motor idled good, so I let it sit and idle for a few minutes to warm up while I checked for any leaks or other issues. After it warmed up, I backed the truck out of the garage, and it started dropping cylinders (misfiring) before I got to the end of the driveway. I spent the next couple of days banging my head against the wall trying to chase down the source of the misfire.

Clues: The fuel system was in good shape, and not the source of the misfire.
No Electronics, 100% mechanical Fuel Injection
The valve train was bone stock from International, with hydraulic roller lifters and stamped steel rockers.
The engine previously had about 110,000 miles on it.

The offending creature for those of you who have never laid hands on one of these dinosaurs.

 

You must have put some of that Chevy oil in it, the SBF only runs on the good stuff!

 

Interesting guess, but it's an International diesel... so that's not it.

Imma gonna go with valve adjustment... adjusted wrong, lifters pumped up, hit the pistons, no seal on the combustion chamber.

3blap.

 

What does a diesel have to do with the sbf or old cars or anything? Diesel’s for washing parts…

 

3blapcam, you are getting warm. However, there is no adjustment on the valve train for this engine, and the engine did run good for probably 15 mins before something went wrong.

 

The problem had nothing to do with the fuel type. But, this problem could occur on any engine that uses a lifter, pushrod, and rocker, which except for the Flathead and SOHC crowd, covers all the rest of the HAMB friendly motors.

 

You're 100% correct, it has NOTHING to do with an SBF, but you need to catch up. That other problem was solved already. A new problem has been presented, and it has to do with an International Diesel. Did you see the post before yours?

FM... smoked the cam?

3blap.

 

Nope. Rockers popped off the intake side push rods on cylinders 6 & 8. I have never had that happen to me before, and I spent 2 days chasing ghosts in a perfectly good fuel system. Still not sure exactly where I went wrong, maybe didn't get the push rods centered in the cup on the rocker, or didn't properly torque the rockers all the way down. Finally pulled the valve cover off to check something else, and was smacked with the obvious answer. Checked to make sure the push rods weren't bent, re-***embled and everything was good.

If I had spent a bit more time thinking about the process I had just completed to re-***emble the heads back onto the engine, it should have been an obvious thing to check. Sometimes we are our own worst enemies.

 

Next time, try removing the plug wires one at a time to help you narrow down the problem….. oh wait….

 

You can achieve the same effect by cracking the injector lines